Electrical connector



Nov. 5, 1957 A. G. LUISADA 2,812,507

ELECTRICAL CONNECTOR Filed Nov. 17, 1955 s n 4c ATTOR/Vfy United States Patent ELECTRICAL' CONNECTOR August ,G.- Luisada, .Carbondale,FPa., as'signor to Leonard TPLFrieQder, Great Neck, N. Y.

. Application November17,-1955,--Serial No. 547,524

.-8. Claims. (Cl. 339-,107)

This linvention -1'elates .to .-electrical connectors, and

particularly to connectors of ,the plug .and jacktype,

which maybe.subjectto-severe strains in the attached .wires, whichstrains may resultv in the Wear or fraying of the .insulation of the wire or. in pulling the Wire loose from theconnector plug.

Therpresentconnector was .particularly designed for;

use in. connecting earphones attached :to a safetyhelmet .to :associated electrical equipmentcarried on the ,body of the person. using that equipment.

A connector. of the type described .includes a flexible wire comprisingone or more insulatedconductors.con- .nectedto a:plug ofrigid insulatingmaterial .whichis attachedmore or .less rigidly to .a similarlyrigidjack. The. conductorsv .are connectedelectrically to contacts. in the plug orjack. The .stressesntransmitted through the wire to -the plug may be classified as either. tension stresses,

.duetopulling ofthe vwi1:e, or torsional stressesdueto twisting of the wire. It isdesired tohavethe stresses which pass along the Wire transmitted through the insulation of' the :wire to the "plug, so that the electrical connection willnot be disturbe'dby'those stresses.

.An object of the present invention is to.provide an improved electrical connector of the type described.

Another object is to provide an electricalconnector of the. type; described including improvedmeans for transmitting tensional and torsional forces through thelinsu-a lating covering of the wire to an'insulating plug.

Other objects and advantages oft-he invention will become apparent "from a consideration of the following description and claims, taken together with the accompanying drawing.

In the drawing:

Fig. 1 is a plan view of an electrical connector embodying the invention;

Fig. 2 is a front elevational view of the connector of Fig. 1;

Fig. 3 is a sectional view taken on the line IIIIII of Fig. 2, with certain parts broken away;

Fig. 4 is a sectional view taken on the line IV-IV of Fig. 1;

Fig. 5 is a sectional view taken on the line VV of V Fig. 4; and

Fig. 6 is a sectional View taken no the line VI-VI of Fig. 4.

There is shown in the drawing, a wire generally indicated at 1, connected to a plug 2. The plug 2 is longitudinally split into upper and lower sections 3 and 4 which are held together by bolts 5 and nuts 6. The two sections 3 and 4 of the plug have opposed facing recesses 30, 4c, for receiving the end of the wire and other internal parts of the connector. The wire is illustrated as having two internal conductors 7, although it should be readily understood that the number of conductors is immaterial and that the invention is applicable to a cable of one or more conductors. The conductors are encircled by a braided sleeve, 8 of tough flexible material,

such as.heavy..cotton. Acove'ring 9 of. molded,.plastic material encircleslthesleeve'tl. -The covering orsheath i9.includes .a gradually tapered portion extending outwardly from the plug for a substantial .distance and 5 decreasing in thickness .in a direction away from the plug,

.until it. finally reachesthe thickness 'illustratedat-10. in

Fig. 3.

The sheath'9. terminates short of the'endsof the wires 7. Adjacent its end, the sheath 9. isprovided with.a 10 circular flange 10, .a portion 11 of a generally elliptical cross-section,anotherflange .12, circular like vtheflange .10 but substantially thicker, and finally a portion 13.of rectangular cross-section. .The plug sections3 .and 4 have their central: recesses 3b, 4b, formed to correspond totheshape of the portions .10, 11, 12 and 13 of'the sheath, .ihe variousparts of the sheath fittingclosely within the, plug sections. .The conductors "7 have slack end: portions 711 attached, as by soldering,.to. leaf spring conductors.14. 'The conductors 14, .and backing leaf springs. 16,. are attached,.as by rivets 17 to squared bases formedon theinner ends of hollow cylindrical sockets 15, adapted to. receive. pins on a. cooperating plug. The free ends of .the conductors 14 extend through openings 15a in. the sidesof the sockets 15, soas toengagefric- .tionally pins which may be received therein.

Anytensionstress applied to the wire 1 is transmitted totheplugl throughthe flange ltl. Sincethe flange 10 -is.relativelythin it. maydeform in the presenceof-such stresses, in.-whichv case part of the stress is taken up and transmitted to the .plugby the heavier flange .12. Light torsional stresses areabsorbed by theelliptical section 410- of the sheathand transmitted thereby to the plug. The section. .11 is capable .of some deformation under suchstresses. The -stresses are further absorbed and 35. transmitted. to the, plug .by. the rectangular sheath: section .13,-which. is effectiveto. absorbeven greater stresses.

.Itmay be. seen. that .the structure shown and described ,is capable of transmitting torsional. and. tensional stresses of substantial. magnitude between the wiresl and the. plug 2, without .transrnittingthose stresses through the ends 7a..of.the.cond uctors.7 and the other electrically conductive, parts.

The plugs 3 and 4 have central portions Fla-and 4a, best seen'in Fig. "5, which are offs'etfrom the plane of their edge portions 3b and 4b. The central recesses which receive the flanged and noncircular portions of the sheath 9 are located in'these offset portions 3a and 4a. By providing this offset arrangement, the center line of the wire and of the plug may be offset laterally from the center line of the connector end.

While I have shown and described a preferred embodiment of my invention, other modifications thereof will readily occur to those skilled in the art, andI therefore intend my invention to be limited only by the appended claims.

I claim:

1. An electrical connector comprising at least one flexible conductor, a sheath for said conductor of yieldable, resilient insulating material terminating at a point adjacent but spaced from an end of the conductor, a hollow plug of rigid insulating material receiving said end of said conductor and the adjacent end of the sheath, contact means in said plug, means conductively connecting the end of the conductor to the contact means, and means for relieving torsional stresses in said conductor and preventing said stresses from reaching said connecting means, said torsional stress relieving means comprising a portion of said sheath of substantially elliptical cross section and 0 means in said plug defining a cooperating substantially elliptical recess for receiving said substantially elliptical sheath portion.

2. An electrical connector as defined in claim 1, including means for relieving tension stresses in said conductor and preventing said tension stresses from reaching said connecting means, said tension stress relieving means comprising an annular flange on said sheath and spaced lengthwise thereof from said torsional. stress relieving means, and means in said plug defining a recess for receiving said flange.

3. An electrical connector, as defined in claim 1, in which said sheath comprises a braided sleeve encircling the conductor, and a layer of molded plastic insulating material encircling the sleeve, said sheath portion being molded in said layer.

4. An electrical connector comprising at least one conductor, a sheath for said conductor of yieldable, resilient insulating material terminating at a point adjacent but spaced from the end of the conductor, a hollow plug of rigid insulating material receiving said end of said conductor and the adjacent end of the sheath, contact means in said plug, means conductively connecting the end of the conductor to the contact means, and means for relieving torsional and tensional stresses in said conductor and preventing said stresses from reaching said connecting means, said strain relieving means comprising four adjacent portions extending along said sheath from the end thereof, the portion nearest the end being of rectangular cross-section, the second portion from the end being somewhat longer and of circular cross-section, the third I portion from the end being of substantially elliptical cross-section and shorter than said second portion, the fourth portion from the end being of circular crosssection, said second and fourth portions being of substantially greater diameter than the rest of the sheath,

recess defining means being located in said abutting plane portions.

7. An electrical connector as defined in claim 1, in which said torsional stress relieving means comprises a further portion of said sheath of rectangular cross-section spaced lengthwise of the sheath and toward the end thereof from said portion of substantially elliptical crosssection, and means in said plug defining a conforming recess for receiving said portion of rectangular crosssection, said elliptical portion of the sheath being effective to transfer from the conductor to the plug torsional stresses of less than a predetermined value sufiicient to deform said elliptical portion, and said rectangular portion of the sheath being efiective to transfer torsional stresses to the plug from the sheath after said elliptical portion has been deformed.

8. An electrical connector comprising at least one flexible conductor, a sheath for said conductor of yieldable, resilient insulating material terminating at a point adjacent but spaced from an end of the conductor, a hollow plug of rigid insulating material receiving said end of said conductor and the adjacent end of the sheath, contact means in said plug, means conductively connecting the end of the conductor to the contact means, and means for relieving tension stresses in said conductor and preventing said tension stresses from reaching said connecting means, said tension stress relieving means comprising two flanges, encircling said sheath and spaced lengthwise thereof, the flange nearest the end of the sheath being substantially thicker than the other flange, and means in said plug defining recesses for receiving said flanges, said other flange being effective to transfer from the conductor to the plug tensile stresses of less than a predetermined value sufficient to deform said other flange, and said flange nearest the end of the sheath being effective to 7 transfer tensile stresses to the plug from the sheath after the conductor, and a layer of molded plastic insulating offset laterally from the adjacent edge portions, said said one flange has been deformed.

References, Cited in the file of this patent UNITED STATES PATENTS 1,672,521 Goldrick June 5, 1928 1,804,474 Martin May 12, 1931 1,918,071 Watts July 11, 1933 2,209,814 Finger July 30, 19 40 2,272,432 Rogie Feb. 10, 1942 2,686,828 Guy Aug. 17, 1954 2,710,949 Hoppe June 14, 1955 

